Method of forming a stressed passivation film using a microwave-assisted oxidation process

ABSTRACT

A method for forming a stressed passivation film. In one embodiment, the method includes depositing a silicon nitride film over an integrated circuit structure on a substrate and embedding oxygen into a surface of the silicon nitride film by exposing the silicon nitride film to a process gas containing an oxygen-containing or an oxygen- and nitrogen-containing gas excited by plasma induced dissociation based on microwave irradiation via a plane antenna member having a plurality of slots, wherein the plane antenna member faces the substrate surface containing the silicon nitride film. The method further includes heat-treating the oxygen-embedded silicon nitride film to form a stressed silicon oxynitride film.

CROSS-REFERENCED TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser.No. 12/______ (Attorney Docket No. TTCA-238), entitled “METHOD OFFORMING A STRESSED PASSIVATION FILM USING AN NON-IONIZINGELECTROMAGNETIC RADIATION-ASSISTED OXIDATION PROCESS,” filed on the samedate as the present application, the entire content of which is herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to forming a stressed passivation film insemiconductor processing, and more particularly to a method of forming astressed silicon oxynitride film.

BACKGROUND OF THE INVENTION

In the construction of integrated circuit devices, a topside orpassivation film of a dielectric material is conventionally providedover the underlying layers containing the integrated circuit structure.This film, in addition to functioning as an insulation film, acts toprotect the underlying structure from moisture and ion contaminationthat can damage or destroy the structure by causing corrosion andelectrical shorts.

Silicon nitride is known as a satisfactory insulation layer for formingsuch a passivation film, due at least in part to its high resistance tomoisture and hydrogen penetration. Moreover, the diffusivity of variousimpurities, such as sodium, is much lower in silicon nitride than inother insulators, such as silicon dioxide. Thus, integrated circuitsmade with a silicon nitride passivation layer are less susceptible toionic contamination problems.

Recent innovations to improve complementary metal oxide semiconductor(CMOS) transistor performance have created an industry need for stressedceramic layers compatible with current ultra-large scale integration(ULSI) techniques. In particular, channel carrier mobility for anegative metal oxide semiconductor (NMOS) transistors can be increasedthrough introduction of tensile uniaxial or biaxial strain on a channelregion of a MOS transistor. Typically, this has been accomplished bydeposition of highly tensile stressed silicon nitride as a cap layerover the source/drain regions. While other novel materials may beexplored for this application, silicon nitride and silicon nitride basedmaterials are preferable due to their compatibility with existingfabrication processes.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, a method is described forforming a stressed passivation film over an integrated circuitstructure. The stressed passivation film is formed by depositing asilicon nitride film over the integrated circuit structure andsubsequently oxidizing at least a top portion of the silicon nitridefilm to create or increase stress in the film and improve theperformance of the device containing the integrated circuit structure.According to embodiments of the invention, the oxidation process isperformed using low-energy excited oxygen species that eliminate or atleast significantly reduce oxidation and/or damage to underlyingmaterials and devices.

In one embodiment, the method includes depositing a silicon nitride filmover an integrated circuit structure on a substrate and embedding oxygeninto a surface of the silicon nitride film by exposing the siliconnitride film to a process gas containing an oxygen-containing gas or anoxygen- and nitrogen-containing gas excited by plasma induceddissociation using plasma based on microwave irradiation via a planeantenna member having a plurality of slots, where the plane antennamember faces the substrate containing the silicon nitride film. Themethod further includes heat-treating the oxygen-embedded siliconnitride film to form a stressed silicon oxynitride film.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic showing a cross-sectional view of a MOS deviceincluding a stressed silicon oxynitride film according to an embodimentof the invention;

FIG. 2 is a schematic diagram of a vacuum processing tool for forming astressed silicon oxynitride film according to an embodiment of theinvention;

FIG. 3 is a process flow diagram for forming a stressed siliconoxynitride film on a substrate according to an embodiment of theinvention;

FIG. 4 is a process flow diagram for forming a stressed siliconoxynitride film on a substrate according to another embodiment of theinvention;

FIG. 5 is a schematic diagram of a film deposition system for depositinga silicon nitride film on a substrate according to one embodiment of theinvention;

FIG. 6 is a schematic diagram of a processing system containing anon-ionizing electromagnetic radiation source for performing anoxidation process according to one embodiment of the invention;

FIG. 7 is a schematic diagram of another processing system containing anon-ionizing electromagnetic radiation source for performing anoxidation process according to one embodiment of the invention; and

FIG. 8 is a schematic diagram of a plasma processing system containing aslot plane antenna (SPA) plasma source for performing an oxidationprocess according to one embodiment of the invention.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

Methods for forming a stressed passivation film in semiconductorprocessing are described in various embodiments. One skilled in therelevant art will recognize that the various embodiments may bepracticed without one or more of the specific details, or with otherreplacement and/or additional methods, materials, or components. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of variousembodiments of the invention. Similarly, for purposes of explanation,specific numbers, materials, and configurations are set forth in orderto provide a thorough understanding of the invention. Furthermore, it isunderstood that the various embodiments shown in the figures areillustrative representations and are not necessarily drawn to scale.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, material, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the invention, but do not denote that theyare present in every embodiment. Thus, the appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily referring to the same embodimentof the invention.

There is a general need for new methods for forming stressed passivationfilms under well-controlled process conditions that provide greatflexibility for tailoring the material properties and the stress inducedin the films that improve device performance. The new methods are neededfor replacing ion implantation methods that utilize high kinetic energyion beams and methods that utilize direct exposure of the films to highkinetic energy oxygen (O) species such as O ions excited by conventionalplasma processing systems and plasma processing conditions. Thesemethods to be replaced have several drawbacks, including charging damageof the exposed films and poor control over the depth profiles ofelements embedded in the films. These drawbacks become increasingly moreimportant as films in semiconductor devices become increasingly thinner.

In particular, new methods are needed that integrate deposition ofsilicon nitride or silicon nitride based films and in-situ (without airexposure) oxidation of the silicon nitride or silicon nitride based filmby low-energy excited oxygen (O) species in a process gas containing anoxygen-containing gas (e.g., O₂, H₂O, or H₂O₂) or an oxygen- andnitrogen-containing gas (e.g., NO, N₂O, or NO₂). Embodiments of theinvention use low-energy excited oxygen species in an oxidation processwhere the oxidation of the films does not exceed the thickness of thefilms, thereby eliminating or at least significantly reducing oxidationand/or damage to underlying materials and devices. The in-situprocessing provides excellent control over the extent of film oxidationand oxidation depth profile, and reduces contamination due to theabsence of atmospheric exposure during processing.

The silicon nitride films contain silicon (Si) and nitrogen (N), forexample as SiN_(x), and the silicon oxynitride films contain Si, N, andO, for example as SiN_(x)O_(y). The silicon nitride based films can, inaddition to Si and N, further contain carbon (C), hydrogen (H), or bothC and H. Furthermore, the silicon oxynitride films can, in addition toSi, N, and O, further contain C, H, or both C and H. In the followingdescription, silicon nitride films and silicon nitride based films arereferred to simply as silicon nitride films. Composition of a siliconoxynitride film can vary from an external surface of the siliconoxynitride film exposed to the low-energy oxygen species to an interfacebetween the silicon oxynitride film and a non-oxidized portion of thesilicon nitride film. However, the interface may not be abrupt, but maybe described by a smooth, continuous reduction in oxygen concentrationfrom the oxygen content of the external surface of the siliconoxynitride film to the oxygen content of the silicon nitride film.According to an embodiment of the invention, a thickness of the siliconnitride film can be between about 5 nanometers (nm) and about 50 nm anda thickness of a surface layer of the silicon nitride film containingembedded oxygen can be between about 3 nm and about 10 nm.

FIG. 1 is a schematic showing a cross-sectional view of a MOS deviceincluding a stressed silicon oxynitride film according to an embodimentof the invention. The device 180 includes a substrate 182 having dopedregions 183 and 184 (e.g., source and drain), a gate stack 190, and astressed silicon oxynitride film 192. The substrate 182 can, forexample, be a semiconductor substrate, such as a silicon substrate, asilicon germanium substrate, a germanium substrate, a glass substrate, aLCD substrate, or a compound semiconductor substrate such as for exampleGaAs. The substrate 182 can be of any size, for example, a 200 mmsubstrate, a 300 mm substrate, or an even larger substrate.

The gate stack 190 includes a dielectric layer 186 on the channel region185. The dielectric layer 186 can for example include a silicon dioxidelayer, a silicon nitride layer, a silicon oxynitride layer, or acombination thereof, or any other appropriate material. The dielectriclayer 186 can further include a high-dielectric constant (high-k)material. The high-k material can for example include a metal oxide, ametal oxynitride, a metal silicate, or a metal silicon oxynitride.Examples of the high-k materials include Ta₂O₅, TiO₂, Al₂O₃, Y₂O₃, BaO,ZrO₂, HfO₂, SrO_(x), LaO_(x), YO_(x), ZrNO_(x), HfNO_(x), ZrSiO_(x),HfSiO_(x), TaSiO_(x), SrSiO_(x), LaSiO_(x), YSiO_(x), ZrSiNO_(x), orHfSiNO_(x), or a combination of two or more thereof. The high-k materialis not limited to the above-mentioned materials and may contain othersimple or complex oxides, silicates, and oxynitrides suitable forfabrication of advanced semiconductor devices. In one example, athickness of the high-k material can between about 1 nm and about 5 nm,or between about 1.2 nm and about 3 nm.

In one embodiment, a conductive layer 187 (e.g., a gate electrode layer)is formed on the dielectric layer 186, and a silicide layer 188 isformed on the conductive layer 187 to reduce the electrical resistanceof the conductive layer 187. A cap layer 189 can be positioned at thetop of the gate stack 190 to protect the gate stack 190. The cap layer189 can, for example, be a silicon nitride or silicon oxynitride layer.In one example, the conductive layer 187 can be doped polycrystallinesilicon (poly-Si), and the silicide layer 188 can be tungsten silicide.Furthermore, the device 180 and the gate stack 190 may include differentand fewer or more layers than shown in FIG. 1. In one example,conductive layer 187 and/or silicide layer 188 may be replaced by ametal gate layer. FIG. 1 further shows a spacer 181 formed on eitherside of the gate stack 190 in order to protect the gate stack 190 fromdamage and ensure electrical performance of the gate stack 190. Inaddition, the spacer 181 can be used as a hard mask for the formation ofthe source 183 and drain 184 of the MOS device 180. Alternatively, inone embodiment of the present invention, more than one spacer 181 may beused. The MOS device depicted in FIG. 1 may be further processed tocomplete a semiconductor device.

In one embodiment of the present invention, the device 180 can be a NMOSdevice where stressed silicon oxynitride film 192 increases channelcarrier mobility through introduction of a tensile stress on the channelregion 185. The stressed silicon oxynitride film 192 can also serve as apassivation film for protecting the device 180. According to oneembodiment of the present invention, the stressed silicon oxynitridefilm 192 may have a tensile stress equal to or greater than about 1.5GPa (1.5×10⁹ Pascal).

FIG. 2 is a schematic diagram of a vacuum processing tool for forming astressed silicon oxynitride film according to an embodiment of theinvention. The vacuum processing tool 500 contains a first substrate(wafer) transfer system 501 that includes cassette modules 501A and501B, and a substrate alignment module 501C. Load-lock chambers 502A and502B are coupled to the substrate transfer system 501 using gate valvesG1 and G2, respectively. The first substrate transfer system 501 ismaintained at atmospheric pressure but a clean environment is providedby purging with an inert gas. The load lock chambers 502A and 502B arecoupled to a second substrate transfer system 503 using gate valves G3and G4. The second substrate transfer system 503 may be maintained at abase pressure of about 100 mTorr, or lower, using a turbomolecular pump(not shown). The second substrate transfer system 503 includes asubstrate transfer robot and is coupled to degassing system 504A,precleaning system 504B for precleaning a substrate or an integratedcircuit structure on a substrate prior to further processing, andauxiliary processing system 504C. The processing systems 504A, 504B, and504C are coupled to the second substrate transfer system 503 using gatevalves G5, G6, and G7, respectively.

Furthermore, the second substrate transfer system 503 is coupled to athird substrate transfer system 505 through substrate handling chamber504D and gate valve G8. As in the second substrate transfer system 503,the third substrate transfer system 505 may be maintained at a basepressure of about 100 mTorr, or lower, using a turbomolecular pump (notshown). The third substrate transfer system 505 includes a substratetransfer robot. Coupled to the third substrate transfer system 505 arefirst processing system 506A configured for depositing a silicon nitridefilm on a substrate, and second processing system 506D configured forembedding oxygen into a surface of a silicon nitride film by exposingthe silicon nitride film to a process gas containing anoxygen-containing gas (e.g., O₂, H₂O, or H₂O₂) or an oxygen- andnitrogen-containing gas (e.g., NO, N₂O, or NO₂) exited by plasma induceddissociation using plasma formed by microwave irradiation via a planeantenna member having a plurality of slots. Furthermore, coupled to thethird substrate transfer system 505 are third processing system 506Bconfigured for embedding oxygen into a surface of a silicon nitride filmby exposing the silicon nitride film to a process gas containing oxygenradicals formed by non-ionizing electromagnetic (e.g., ultraviolet (UV))radiation induced dissociation of the oxygen-containing gas or theoxygen- and nitrogen-containing gas, and fourth processing system 506Cconfigured for low-pressure heat-treating of silicon oxynitride filmsfollowing processing of the silicon nitride films in processing systems506B or 506D. The processing systems 506A, 506B, 506C, and 506D arecoupled to the substrate transfer system 505 using gate valves G9, G10,G11, and G12, respectively.

According to one embodiment of the invention, the first processingsystem 506A can include a film deposition system 1 schematically shownin FIG. 5. According to an embodiment of the invention, the secondprocessing system 506D can be a plasma processing system containing aslot plane antenna (SPA) plasma source; one example of such a plasmaprocessing system is shown in FIG. 8. According to an embodiment of theinvention, the third processing system 506B can be a processing systemcontaining a non-ionizing electromagnetic ultraviolet (UV) excitationsource; examples of such a processing system are shown in FIGS. 6 and 7.The third substrate transfer system 505 and processing systems 506A-506Dare capable of maintaining a base pressure of background gases at about100 mTorr, or lower, during the integrated processing, thereby enablingformation of stressed silicon oxynitride films under well-controlledprocess conditions that provide great flexibility for tailoring thematerial properties and stress induced in the films.

The vacuum processing tool 500 includes a controller 510 that can becoupled to and control any or all of the processing systems andprocessing elements depicted in FIG. 2 during the integrated substrateprocessing. Alternatively, or in addition, controller 510 can be coupledto one or more additional controllers/computers (not shown), andcontroller 510 can obtain setup and/or configuration information from anadditional controller/computer. The controller 510 can be used toconfigure any or all of the processing systems and processing elements,and the controller 510 can collect, provide, process, store, and displaydata from any or all of the processing systems and processing elements.The controller 510 can include a number of applications for controllingany or all of the processing systems and processing elements. Forexample, controller 510 can include a graphic user interface (GUI)component (not shown) that can provide easy to use interfaces thatenable a user to monitor and/or control one or more processing systemsprocessing elements.

The controller 510 can include a microprocessor, memory, and a digitalI/O port capable of generating control voltages sufficient tocommunicate, activate inputs, and exchange information with the vacuumprocessing tool 500 as well as monitor outputs from the vacuumprocessing tool 500. For example, a program stored in the memory may beutilized to activate the inputs of the vacuum processing tool 500according to a process recipe in order to perform integrated substrateprocessing.

However, the controller 510 may be implemented as a general purposecomputer system that performs a portion or all of the microprocessorbased processing steps of the invention in response to a processorexecuting one or more sequences of one or more instructions contained ina memory. Such instructions may be read into the controller memory fromanother computer readable medium, such as a hard disk or a removablemedia drive. One or more processors in a multi-processing arrangementmay also be employed as the controller microprocessor to execute thesequences of instructions contained in main memory. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions. Thus, embodiments are notlimited to any specific combination of hardware circuitry and software.

The controller 510 includes at least one computer readable medium ormemory, such as the controller memory, for holding instructionsprogrammed according to the teachings of the invention and forcontaining data structures, tables, records, or other data that may benecessary to implement the present invention. Examples of computerreadable media are compact discs, hard disks, floppy disks, tape,magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM,SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), orany other optical medium, punch cards, paper tape, or other physicalmedium with patterns of holes, a carrier wave (described below), or anyother medium from which a computer can read.

Stored on any one or on a combination of computer readable media issoftware for controlling the controller 510, for driving a device ordevices for implementing the invention, and/or for enabling thecontroller 510 to interact with a human user. Such software may include,but is not limited to, device drivers, operating systems, developmenttools, and applications software. Such computer readable media furtherincludes the computer program product of the present invention forperforming all or a portion (if processing is distributed) of theprocessing performed in implementing embodiments of the invention.

The computer code devices of the present invention may be anyinterpretable or executable code mechanism, including but not limited toscripts, interpretable programs, dynamic link libraries (DLLs), Javaclasses, and complete executable programs. Moreover, parts of theprocessing of the present invention may be distributed for betterperformance, reliability, and/or cost.

The controller 510 may be locally located relative to the vacuumprocessing tool 500, or it may be remotely located relative to thevacuum processing tool 500. For example, the controller 510 may exchangedata with the vacuum processing tool 500 using at least one of a directconnection, an intranet, the Internet and a wireless connection. Thecontroller 510 may be coupled to an intranet at, for example, a customersite (i.e., a device maker, etc.), or it may be coupled to an intranetat, for example, a vendor site (i.e., an equipment manufacturer).Additionally, for example, the controller 510 may be coupled to theInternet. Furthermore, another computer (i.e., controller, server, etc.)may access, for example, the controller 510 to exchange data via atleast one of a direct connection, an intranet, and the Internet. As alsowould be appreciated by those skilled in the art, the controller 510 mayexchange data with the vacuum processing tool 500 via a wirelessconnection.

As those skilled in the art will readily recognize, embodiments of theinvention may not require the use of all the processing systems of thevacuum processing tool 500 depicted in FIG. 2. For example, according toone embodiment, either the second processing system 506D or the thirdprocessing system 506B are used for embedding oxygen into a siliconnitride film. Thus, some embodiments of the invention may include theuse of less than all the processing systems depicted in FIG. 2.

FIG. 3 is a process flow diagram for forming a stressed siliconoxynitride film on a substrate according to an embodiment of theinvention. In block 302 of process flow 300, a substrate is provided invacuum processing tool, for example vacuum processing tool 500 depictedin FIG. 2. The substrate can, for example, be a Si substrate. A Sisubstrate can be of n- or p-type, depending on the type of device beingformed. The substrate can contain an integrated structure thereon, forexample the gate stack 190 depicted in FIG. 1.

According to one embodiment of the invention, the substrate is providedin the cassette modules 501A or 501B for processing in the vacuumprocessing tool 500. The substrate is introduced into the substratetransfer system 503 from the substrate transfer system 501 through thegate valve G1 and the load lock chamber 502A or through the gate valveG2 and the load lock chamber 502B, after a substrate aligning step inthe substrate alignment module 501C. The substrate is then transferredfrom the substrate transfer system 503 to the processing system 504Athrough the gate valve G5. In the processing system 504A, the substratemay be degassed by heating and/or exposed to ultraviolet radiation in aninert gas environment to remove water and any residual gas from thesubstrate.

After degassing in the processing system 504A, the substrate is returnedto the substrate transfer system 503 through the gate valve G5, and nextthe substrate is optionally transported to the (precleaning) processingsystem 504B through the gate valve G6. Following the optionalprecleaning, the substrate is returned to the substrate transfer system503 through the gate valve G6, and then transferred to the substratetransfer system 505 from the substrate handling chamber 504D through thegate valve G8. Once in the substrate transfer system 505, the substrateis introduced into the first processing system 506A through the gatevalve G9 for depositing a silicon nitride film on the substrate in block304.

After deposition of the silicon nitride film in the first processingsystem 506A, the substrate is returned to the third substrate transfersystem 505 through the gate valve G9. Next, the substrate is introducedinto the third processing system 506B through the gate valve G10 forembedding oxygen into a surface of the silicon nitride film in block306. The oxidizing in block 306 includes exposing the silicon nitridefilm to a process gas containing oxygen radicals formed by non-ionizingelectromagnetic radiation induced dissociation of an oxygen-containinggas or an oxygen- and nitrogen-containing gas. In one example, the thirdprocessing system 506B can include a processing system 101 schematicallyshown in FIG. 6. In another example, the third processing system 506Bcan include a processing system 550 schematically shown in FIG. 7.

Oxidation of a silicon nitride film in the processing system 101 caninclude a substrate temperature between about 25° C. and about 800° C.,for example about 400° C. Alternatively, the substrate temperature canbe between about 400° C. and about 700° C. The pressure in the processchamber 450 can, for example, be maintained between about 100 mTorr andabout 10 Torr, for example about 50 mTorr. Alternatively, the pressurecan be maintained between about 20 mTorr and about 1 Torr.

Following the oxidation process in block 306, the substrate is returnedto the substrate transfer system 505 through the gate valve G12 andintroduced into the fourth processing system 506C through the gate valveG11 for heat-treating the oxygen-embedded silicon nitride film in block308 to form a silicon oxynitride film with a desired oxygen depthprofile (oxygen concentration as a function of depth in the siliconoxynitride film) and to improve the electrical and material propertiesof the silicon oxynitride film.

According to embodiments of the invention, the heat-treating can beperformed in the fourth processing system 506C as described above, butalternatively or in addition, the heat-treating may be performed inprocessing systems 506A, 506B, or 506D. According to one embodiment, thestep of embedding oxygen into a surface of the silicon nitride film inblock 306 can at least partially overlap with the heat-treating step inblock 308. According to another embodiment, the steps in blocks 306 and308 may have no temporal overlap. The heat-treating conditions caninclude a pressure of about 50 mTorr to about 760 Torr, or a pressure ofabout 1 Torr to about 10 Torr, using a gas containing O₂, N₂, H₂, Ar,He, Ne, Xe, or Kr, or any combination thereof at a flow rate of 0 to 20standard liters per minute (slm), or at a flow rate of 0.1 slm to 5 slm.The heat-treating may be carried out for a time period between about 5seconds and about 5 minutes, or between about 30 seconds and about 2minutes.

After the heat-treating in block 308, the heat-treated substrate isreturned to the substrate transfer system 505 and to the substratetransfer system 503 through the gate valve G11 and the substratehandling chamber 504D. Thereafter, the substrate is returned to thesubstrate transfer system 501 from the substrate transfer system 503through the gate valve G3, load lock chamber 502A and the gate valve G1,or through the gate valve G4, the load lock chamber 502B and the gatevalve G2. Next, the substrate is returned to the cassette module 501A or501B and removed from the vacuum processing tool 500.

According to one embodiment of the invention, the depositing andoxidizing steps in blocks 304 and 306 may be sequentially performed anynumber of times to form a plurality of oxygen-embedded silicon nitridefilms that may subsequently be heat-treated in block 308 to form aplurality of silicon oxynitride films. Alternatively, each of theoxygen-embedded silicon nitride films may be heat-treated before thenext silicon nitride film is deposited thereon. According to oneembodiment, the step of embedding oxygen into a surface of the siliconnitride film in block 306 can at least partially overlap with theheat-treating step in block 308.

FIG. 4 is a process flow diagram for forming a stressed siliconoxynitride film on a substrate according to another embodiment of theinvention. The process flow 400 in FIG. 4 is similar to the process flow300 in FIG. 3, and includes, in block 402, providing a substrate in avacuum processing tool, for example vacuum processing tool 500 depictedin FIG. 2. The substrate can, for example, be a Si substrate. A Sisubstrate can be of n- or p-type, depending on the type of device beingformed. The substrate can contain an integrated structure thereon, forexample the gate stack 190 depicted in FIG. 1. After degassing andoptional precleaning, the substrate is introduced into the firstprocessing system 506A through the gate valve G9 for depositing asilicon nitride film on the substrate in block 404. After deposition ofthe silicon nitride film, the substrate is returned to the substratetransfer system 505 through the gate valve G9.

Next, the substrate is introduced into the second processing system 506Dthrough the gate valve G12 for embedding oxygen into a surface of thesilicon nitride film in block 406. The oxidizing includes exposure to aprocess gas containing an oxygen-containing gas or an oxygen- andnitrogen-containing gas excited by plasma induced dissociation usingplasma based on microwave irradiation via a plane antenna member havinga plurality of slots, where the plane antenna member faces an uppersurface of a substrate to be processed. In one example, the secondprocessing system 506D can include a plasma processing system 410schematically shown in FIG. 8.

According to one embodiment of the invention, the oxidizing in block 406can further include simultaneously exposing the silicon nitride film tooxygen radicals formed by remote plasma induced dissociation of a secondprocess gas comprising an oxygen-containing gas or an oxygen- andnitrogen-containing gas. The remote plasma source is coupled to theprocess chamber containing the silicon nitride film. Thus, the siliconnitride film is not exposed directly to the remote plasma source but tooxygen radicals formed by the remote plasma induced dissociation of thesecond process gas. The remote plasma source can couple radio frequency(RF) power to the second process gas, and the oxygen radicals aresubsequently flowed into the process chamber using the gas line andexposed to the silicon nitride film. In one example, the plasmaprocessing system 410 schematically shown in FIG. 8 is configured forexposing the silicon nitride film to oxygen radicals formed by remoteplasma induced dissociation of a process gas comprising anoxygen-containing gas or an oxygen- and nitrogen-containing gas.According to one embodiment of the invention, exposure of the siliconnitride film to the oxygen radicals from the remote plasma source and tothe oxygen gas excited by plasma induced dissociation based on microwaveirradiation via a plane antenna member having plurality of slots canhave at least partial temporal overlap. According to another embodiment,the exposures of the silicon nitride film to oxygen radicals formed bythe remote plasma source can be performed before or after the embeddingin block 406.

Next, the substrate is returned to the substrate transfer system 505through the gate valve G12 and introduced into the fourth processingsystem 506C through the gate valve G11 for heat-treating theoxygen-embedded silicon nitride film in block 408. Next, theheat-treated substrate is returned to the substrate transfer system 505and removed from the vacuum processing tool 500 as described above.

FIG. 5 is a schematic diagram of a film deposition system for depositinga silicon nitride film on a substrate according to one embodiment of theinvention. The film deposition system 1 is capable of depositing asilicon nitride film on substrate 25 by a thermal chemical vapordeposition (CVD) process, a plasma-enhanced CVD (PECVD) process, or anatomic layer deposition (ALD) process, for example. The film depositionsystem 1 contains a process chamber 10 having a substrate holder 20configured to support the substrate 25 to be processed. The substrateholder 20 is mounted on a pedestal 5 on a lower surface 65 of thesubstrate holder 20.

The substrate 25 is transferred into and out of the process chamber 10through a gate valve G9 via substrate transfer system 505. Whentransferred into the process chamber 10, the substrate 25 is received bya lift mechanism 48 containing substrate lift pins 22 housed in holes 24within the substrate holder 20. The film deposition system 1 containsthree lift pins 22 (only two are shown in FIG. 5). The lift pins 22 aremade of quartz or a ceramic material such as Al₂O₃, SiO₂, or AlN. Oncethe substrate 25 is received from the substrate transfer system 505, itis lowered to an upper surface of the substrate holder 20. The lower endportion of each lift pin 22 rests against a support plate 56 attached toan arm 54. The arm 54 is connected to a rod 46 of an actuator 58positioned below the process chamber 10. The rod 46 extends throughbellows 64 positioned at the bottom on the process chamber 10.

The process chamber 10 contains an upper assembly 30 coupled to a firstprocess material supply system 40, a second process material supplysystem 42, and a purge gas supply system 44. The upper assembly 30 cancontain a showerhead having a large number of gas delivery holes formedin a lower surface of the showerhead and facing the substrate 25 fordelivering gases 15 into processing space 70 above the substrate 25. Thefirst process material supply system 40 and the second process materialsupply system 42 can be configured to simultaneously or alternatelyintroduce first and second process materials to the process chamber 10.The alternation of the introduction of the first and second processmaterials can be cyclical, or it may be acyclical with variable timeperiods between introduction of the first and second process materials.

The first process material can contain a deposition gas containing asilicon precursor which may be delivered to process chamber 10 in agaseous phase with or without the use of a carrier gas. The secondprocess material can contain a reducing agent, which may include anitrogen precursor containing nitrogen to be incorporated in a siliconnitride film formed on the substrate 25. For instance, the reducingagent may be delivered to process chamber 10 in a gaseous phase with orwithout the use of a carrier gas. Examples of silicon precursors includesilane (SiH₄), disilane (Si₂H₆), monochlorosilane (SiH₃Cl),dichlorosilane (SiH₂Cl₂), trichlorosilane (SiHCl₃), hexachlorodisilane(Si₂Cl₆), tetrakis(dimethylamino)silane (TDMAS),tris(dimethylamino)silane (TrDMAS), diethylsilane (Et₂SiH₂),tetrakis(ethylmethylamino)silane (TEMAS), bis(diethylamino)silane,bis(di-isopropylamino)silane (BIPAS), tris(isopropylamino)silane(TIPAS), (di-isopropylamino)silane (DIPAS), andbis(tertiarybutylamino)silane (BTBAS). Examples of nitrogen precursorsinclude N₂, NH₃, N₂H₄, and C₁-C₁₀ alkylhydrazine compounds. Common C₁and C₂ alkylhydrazine compounds include monomethyl-hydrazine (MeNHNH₂),1,1-dimethyl-hydrazine (Me₂NNH₂), and 1,2-dimethyl-hydrazine (MeNHNHMe).

Exemplary processing conditions during deposition of a silicon nitridefilm include a substrate temperature between about 400° C. and about800° C., for example about 700° C., and a process chamber pressurebetween about 50 mTorr and about 200 Torr, for example about 1 Torr.

The purge gas supply system 44 is configured to introduce a purge gas toprocess chamber 10. For example, the introduction of purge gas may occurduring and/or between introduction of the first and second processmaterials to the process chamber 10, or following the introduction ofthe second process material to process chamber 10. The purge gas cancontain an inert gas, such as a noble gas (i.e., helium, neon, argon,xenon, krypton), or nitrogen (N₂), or hydrogen (H₂).

The film deposition system 1 contains a plasma generation systemconfigured to optionally generate plasma in the processing space 70during deposition of the silicon nitride film. The plasma generationsystem includes a first power source 50 coupled to the process chamber10 and configured to couple power to the first process material, or thesecond process material, or both, in the processing space 70 byenergizing the upper assembly 30. The first power source 50 may be avariable power source and may include a radio frequency (RF) generatorand an impedance match network, and may further include an electrodethrough which RF power is coupled to the plasma in process chamber 10.The electrode can be formed in the upper assembly 30, and it can beconfigured to oppose the substrate holder 20. The impedance matchnetwork can be configured to optimize the transfer of RF power from theRF generator to the plasma by matching the output impedance of the matchnetwork with the input impedance of the process chamber, including theelectrode, and plasma. For instance, the impedance match network servesto improve the transfer of RF power to plasma in process chamber 10 byreducing the reflected power. Match network topologies (e.g. L-type,T-type, T-type, etc.) and automatic control methods are well known tothose skilled in the art. A typical frequency for the application of RFpower to the electrode formed in the upper assembly 30 can, for example,range from 10 MHz to 200 MHz and can be 60 MHz, and the RF power appliedcan, for example, be between about 500 Watts (W) and about 2200 W.

Alternatively, the first power source 50 may include a radio frequency(RF) generator and an impedance match network, and may further includean antenna, such as an inductive coil, through which RF power is coupledto plasma in process chamber 10. The antenna can, for example, include ahelical or solenoidal coil, such as in an inductively coupled plasmasource or helicon source, or it can, for example, include a flat coil asin a transformer coupled plasma source.

Alternatively, the first power source 50 may include a microwavefrequency generator, and may further include a microwave antenna andmicrowave window through which microwave power is coupled to plasma inprocess chamber 10. The coupling of microwave power can be accomplishedusing electron cyclotron resonance (ECR) technology, or it may beemployed using surface wave plasma technology, such as a slotted planeantenna (SPA), as described in U.S. Pat. No. 5,024,716, entitled “Plasmaprocessing apparatus for etching, ashing, and film-formation”; thecontents of which are herein incorporated by reference in its entirety.

The film deposition system 1 contains a substrate bias system configuredto optionally generate or assist in generating plasma during depositionof the silicon nitride film. The substrate bias system includes asubstrate power source 52 coupled to the process chamber 10, andconfigured to couple power to the substrate holder 20. The substratepower source 52 contains a RF generator and an impedance match network.The substrate power source 52 is configured to couple power to the firstprocess material, or the second process material, or both, in theprocessing space 70 by energizing an electrode 28 in the substrateholder 20. A typical frequency for the RF bias can range from about 0.1MHz to about 100 MHz, and can be 13.56 MHz. RF bias systems for plasmaprocessing are well known to those skilled in the art. Alternatively, RFpower is applied to the electrode 28 at multiple frequencies.

The film deposition system 1 contains a substrate temperature controlsystem 60 coupled to the substrate holder 20 and configured to elevate,lower, and control the temperature of substrate 25. The substratetemperature control system 60 is coupled to a resistive heating element35 in the substrate holder 20. The substrate temperature control system60 can further contain temperature control elements, such as a coolingsystem including a re-circulating coolant flow that receives heat fromthe substrate holder 20 and transfers heat to a heat exchanger system(not shown). Additionally, the temperature control elements can includeheating/cooling elements which can be included in the substrate holder20, as well as the chamber wall of the process chamber 10 and any othercomponent within the film deposition system 1.

In order to improve the thermal transfer between the substrate 25 andthe substrate holder 20, the substrate holder 20 can include amechanical clamping system, or an electrical clamping system, such as anelectrostatic clamping system, to affix the substrate 25 to an uppersurface of substrate holder 20. Furthermore, the substrate holder 20 canfurther include a substrate backside gas delivery system configured tointroduce gas to the backside of substrate 25 in order to improve thegas-gap thermal conductance between the substrate 25 and the substrateholder 20. Such a system can be utilized when good temperature controlof the substrate 25 is required at elevated or reduced temperatures. Forexample, the substrate backside gas system can contain a two-zone gasdistribution system, wherein the helium gas gap pressure can beindependently varied between the center and the edge of the substrate25.

Furthermore, the process chamber 10 is coupled to a pressure controlsystem 34 that includes a vacuum pumping system and a variable gatevalve for controllably evacuating the process chamber 10 to a pressuresuitable for processing the substrate 25, and suitable for use of thefirst and second process materials. The vacuum pumping system caninclude a turbo-molecular vacuum pump (TMP) or a cryogenic pump capableof a pumping speed up to about 5000 liters per second (and greater). Inconventional plasma processing devices utilized for thin film depositionor dry etching, a 300 to 5000 liter per second TMP is generallyemployed. Moreover, a device for monitoring chamber pressure, forexample a capacitance manometer (not shown) can be coupled to theprocess chamber 10.

The film deposition system 1 contains a controller 55 that is coupled tothe process chamber 10, pressure control system 34, first processmaterial supply system 40, second process material supply system 42,purge gas supply system 44, first power source 50, substrate powersource 52, actuator 58, substrate temperature control system 60, andsubstrate transfer system 505. In addition, the controller 55 can becoupled to one or more additional controllers/computers (not shown), andthe controller 55 can obtain setup and/or configuration information froman additional controller/computer. The controller 55 can be used toconfigure, collect, provide, process, store, and display data from thefilm deposition system 1. The controller 55 can contain a number ofapplications for controlling the film deposition system 1. For example,controller 55 can include a graphic user interface (GUI) component (notshown) that can provide easy to use interfaces that enable a user tomonitor and/or control the film deposition system 1.

The controller 55 can contain a microprocessor, memory, and a digitalI/O port capable of generating control voltages sufficient tocommunicate and activate inputs to the film deposition system 1 as wellas monitor outputs from the film deposition system 1. For example, aprogram stored in the memory may be utilized to activate the inputs ofthe film deposition system 1 according to a process recipe in order toperform a film deposition process. The controller 55 may be implementedas a general purpose computer system that performs a portion or all ofthe microprocessor based processing steps of the invention in responseto a processor executing one or more sequences of one or moreinstructions contained in a memory. Such instructions may be read intothe controller memory from another computer readable medium, such as ahard disk or a removable media drive. One or more processors in amulti-processing arrangement may also be employed as the controllermicroprocessor to execute the sequences of instructions contained inmain memory. In alternative embodiments, hard-wired circuitry may beused in place of or in combination with software instructions. Thus,embodiments are not limited to any specific combination of hardwarecircuitry and software.

The controller 55 includes at least one computer readable medium ormemory, such as the controller memory, for holding instructionsprogrammed according to the teachings of the invention and forcontaining data structures, tables, records, or other data that may benecessary to implement embodiments of the invention. Stored on any oneor on a combination of computer readable media, the present inventionincludes software for controlling the controller 55, for driving adevice or devices for implementing embodiments of the invention, and/orfor enabling the controller to interact with a human user. Such softwaremay include, but is not limited to, device drivers, operating systems,development tools, and applications software. Such computer readablemedia further includes the computer program product of the presentinvention for performing all or a portion (if processing is distributed)of the processing performed in implementing embodiments of theinvention.

FIG. 6 is a schematic diagram of a processing system containing anon-ionizing electromagnetic radiation source for performing anoxidation process according to one embodiment of the invention. Theradiation source can be a UV radiation source or a visible lightradiation source, for example. The processing system 101 contains aprocess chamber 110 having a substrate holder 120 configured to supporta substrate 125. The process chamber 110 further contains anelectromagnetic radiation assembly 130 for exposing the substrate 125 toelectromagnetic radiation. Additionally, the processing system 101contains a power source 150 coupled to the electromagnetic radiationassembly 130, and a substrate temperature control system 160 coupled tosubstrate holder 120 and configured to elevate and control thetemperature of substrate 125. A gas supply system 140 is coupled to theprocess chamber 110, and configured to introduce a process gas toprocess chamber 110. For example, the process gas can include anoxygen-containing gas or an oxygen- and nitrogen-containing gas andoptionally an inert gas such as a noble gas (i.e., helium, neon, argon,xenon, krypton). According to one embodiment of the invention, theprocess gas consists of O₂. Additionally (not shown), a purge gas can beintroduced to process chamber 110. The purge gas may contain an inertgas, such as nitrogen or a noble gas.

The electromagnetic radiation assembly 130 can, for example, contain anultraviolet (UV) radiation source. The UV source may be monochromatic orpolychromatic. Additionally, the UV source can be configured to produceUV radiation 145 at a wavelength sufficient for dissociating anoxygen-containing gas or an oxygen- and nitrogen-containing gas in theprocess gas. In one embodiment, the oxygen-containing gas can contain O₂and the ultraviolet radiation can have a wavelength from about 145 nm toabout 192 nm. Other wavelength may be used for other oxygen-containinggases or oxygen- and nitrogen-containing gases. The electromagneticradiation assembly 130 can operate at a power ranging from about 5mW/cm² to about 50 mW/cm². The electromagnetic radiation assembly 130can include one, two, three, four, or more radiation sources. Thesources can include lamps or lasers or a combination thereof.

The processing system 101 contains a substrate temperature controlsystem 160 coupled to the substrate holder 120 and configured to elevateand control the temperature of substrate 125. Substrate temperaturecontrol system 160 contains temperature control elements, such as aheating system that may contain resistive heating elements, orthermo-electric heaters/coolers. Additionally, substrate temperaturecontrol system 160 may contain a cooling system including are-circulating coolant flow that receives heat from substrate holder 120and transfers heat to a heat exchanger system (not shown), or whenheating, transfers heat from the heat exchanger system. Furthermore, thesubstrate temperature control system 160 may include temperature controlelements disposed in the chamber wall of the process chamber 110 and anyother component within the processing system 101.

Furthermore, the process chamber 110 is further coupled to a pressurecontrol system 132, including a vacuum pumping system 134 and a valve136, through a duct 138, wherein the pressure control system 132 isconfigured to controllably evacuate the process chamber 110 to apressure suitable for processing the substrate 125. Moreover, a devicefor monitoring chamber pressure (not shown) can be coupled to theprocess chamber 110.

Additionally, the processing system 101 contains a controller 170coupled to the process chamber 110, vacuum pumping system 134, gassupply system 140, power source 150, and substrate temperature controlsystem 160. Alternatively, or in addition, controller 170 can be coupledto a one or more additional controllers/computers (not shown), andcontroller 170 can obtain setup and/or configuration information from anadditional controller/computer.

The controller 170 can contain a microprocessor, memory, and a digitalI/O port capable of generating control voltages sufficient tocommunicate and activate inputs to processing system 101 as well asmonitor outputs from processing system 101. For example, a programstored in the memory may be utilized to activate the inputs to theaforementioned components of the processing system 101 according to aprocess recipe in order to perform process.

Oxidation of a silicon nitride film in the processing system 101 caninclude a substrate temperature between about 200° C. and about 800° C.,for example about 700° C. Alternatively, the substrate temperature canbe between about 400° C. and about 700° C. The pressure in the processchamber 110 can, for example, be maintained between about 100 mTorr andabout 20 Torr, for example about 100 mTorr. Alternatively, the pressurecan be maintained between about 20 mTorr and about 1 Torr. According toone embodiment of the invention, the process gas consists of O₂ that maybe introduced into the process chamber 110 at a flow rate between about100 standard cubic centimeters per minute (sccm) and about 2 slm.According to another embodiment of the invention, the process gas canconsist of O₂ and an inert gas such as a noble gas (i.e., helium, neon,argon, xenon, krypton). A flow rate of the inert gas can, for example,be between 0 slm and about 2 slm, or between 0.1 slm and 1 slm. In oneexample, the process gas consists of O₂ and Ar. Exemplary gas exposuretimes are between about 10 seconds and about 5 min, or between about 30seconds and about 2 minutes, for example about 1 minute.

FIG. 7 is a schematic diagram of another processing system containing anon-ionizing radiation source for performing an oxidation processaccording to one embodiment of the invention. The radiation source canbe a UV radiation source or a visible light radiation source, forexample. The processing system 550 includes a process chamber 581accommodating therein a rotatable substrate holder 582 equipped with aheater 583 that can be a resistive heater. Alternatively, the heater 583may be a lamp heater or any other type of heater. Furthermore theprocess chamber 581 contains an exhaust line 590 connected to the bottomportion of the process chamber 581 and to a vacuum pump 587. Thesubstrate holder 582 can be rotated by a drive mechanism (not shown).The process chamber 581 contains a processing space 586 above thesubstrate 525. The inner surface of the process chamber 581 contains aninner liner 584 made of quartz in order to suppress metal contaminationof the substrate 525 to be processed.

The process chamber 581 contains a gas line 588 with a nozzle 589located opposite the exhaust line 590 for flowing a process gascontaining an oxygen-containing gas or an oxygen- andnitrogen-containing gas over the substrate 525. The process gas flowsover the substrate 525 in a processing space 586 and is evacuated fromthe process chamber 581 by the exhaust line 590.

The process gas supplied from the nozzle 589 is activated bynon-ionizing electromagnetic radiation 595 generated by anelectromagnetic radiation source 591 emitting non-ionizingelectromagnetic radiation 595 through a transmissive window 592 (e.g.,quartz) into the processing space 586 between the nozzle 589 and thesubstrate 525. The electromagnetic radiation source 591 is configured togenerate non-ionizing electromagnetic radiation 595 capable ofdissociating the oxygen-containing gas or the oxygen- andnitrogen-containing gas to form neutral O radicals that flow along thesurface of the substrate 100, thereby exposing the substrate 525 to theneutral O radicals. Unlike during plasma processing, substantially noions are formed in the processing space 586 from dissociation of theoxygen-containing gas or oxygen- and nitrogen-containing gas by the UVradiation 595. According to one embodiment of the invention, theelectromagnetic radiation source 591 is configured to generate UVradiation with a wavelength between about 145 nm to about 192 nm, forexample 172 nm. Although only one electromagnetic radiation source 591is depicted in FIG. 7, other embodiments of the invention contemplatethe use of a plurality of electromagnetic radiation sources 591 abovethe substrate 525.

Furthermore, the process chamber 581 contains a remote RF plasma source593 located opposite the exhaust line 590. The remote RF plasma source593 may be utilized to form neutral and ionized plasma-excited speciesthat may assist in the non-ionizing electromagnetic radiation-assistedoxidation process described above. A second process gas containing anoxygen-containing gas or an oxygen- and nitrogen-containing gas can besupplied by gas line 594 to the remote RF plasma source 593 for formingthe plasma-excited oxidation species. The plasma-excited oxidationspecies flow from the remote RF plasma source 593 along the surface ofthe substrate 525, thereby exposing the substrate 525 to theplasma-excited oxidation species. According to one embodiment of theinvention, in addition to exposing the substrate 525 to neutral Oradicals generated by the electromagnetic radiation source 591, thesubstrate may be exposed to oxygen radicals generated by the remote RFplasma source 593 and transported to the processing space 586.

Still referring to FIG. 7, a controller 599 includes a microprocessor, amemory, and a digital I/O port capable of generating control voltagessufficient to communicate and activate inputs of the processing system550 as well as monitor outputs from the processing system 550. Moreover,the controller 599 is coupled to and exchanges information with processchamber 581, the vacuum pump 587, the heater 583, the remote RF plasmasource 593, and the electromagnetic radiation source 591. The controller599 may be implemented as a UNIX-based workstation. Alternatively, thecontroller 599 can be implemented as a general-purpose computer, digitalsignal processing system, etc.

Further details of a processing system containing an UV radiation sourceare described in U.S. Pat. No. 6,927,112, titled “Radical Processing OfA Sub-Nanometer Insulation Film”, the entire contents of which is herebyincorporated by reference.

Oxidation of a silicon nitride film in the processing system 550 caninclude a substrate temperature between about 200° C. and about 800° C.,for example about 700° C. Alternatively, the substrate temperature canbe between about 400° C. and about 700° C. The pressure in the processchamber 110 can, for example, be maintained between about 100 mTorr andabout 20 Torr, for example about 100 mTorr. Alternatively, the pressurecan be maintained between about 20 mTorr and about 1 Torr. According toone embodiment of the invention, the process gas consists of O₂ that maybe introduced into the process chamber 581 at a flow rate between about100 sccm and about 2 slm. According to another embodiment of theinvention, the process gas can consist of O₂ and an inert gas such as anoble gas. A flow rate of the inert gas can, for example, be between 0sccm and about 2 slm. In one example, the process gas consists of O₂ andAr. Exemplary gas exposure times are between about 10 sec and about 5min, for example about 1 min.

FIG. 8 is a schematic diagram of a plasma processing system containing aslot plane antenna (SPA) plasma source for performing an oxidationprocess according to one embodiment of the invention. The plasmaproduced in the plasma processing system 410 is characterized by lowelectron temperature and high plasma density that enables damage-freeoxidation of silicon nitride films according to embodiments of theinvention. The plasma processing system 410 can, for example, be aTRIAS™ SPA processing system from Tokyo Electron Limited, Akasaka,Japan. The plasma processing system 410 contains a process chamber 450having an opening portion 451 in the upper portion of the processchamber 450 that is larger than a substrate 425. A cylindricaldielectric top plate 454 made of quartz or aluminum nitride or aluminumoxide is provided to cover the opening portion 451. Gas lines 472 arelocated in the side wall of the upper portion of process chamber 450below the top plate 454. In one example, the number of gas lines 472 canbe 16 (only two of which are shown in FIG. 8). Alternatively, adifferent number of gas lines 472 can be used. The gas lines 472 can becircumferentially arranged in the process chamber 450, but this is notrequired for the invention. A process gas can be evenly and uniformlysupplied into the plasma region 459 in process chamber 450 from the gaslines 472. The process gas can contain an oxygen-containing gas (e.g.,O₂, H₂O, or H₂O₂), an oxygen- and nitrogen-containing gas (e.g., NO,N₂O, or NO₂), or a combination thereof. The process gas can furthercontain an inert gas such as Ar.

In the plasma processing system 410, microwave power is provided to theprocess chamber 450 through the top plate 454 via a slot plane antenna460 having a plurality of slots 460A. The slot plane antenna 460 facesthe substrate 425 to be processed and the slot plane antenna 460 can bemade from a metal plate, for example copper. In order to supply themicrowave power to the slot plane antenna 460, a waveguide 463 isdisposed on the top plate 454, where the waveguide 463 is connected to amicrowave power supply 461 for generating microwaves with a frequency ofabout 2.45 GHz, for example. The waveguide 463 contains a flat circularwaveguide 463A with a lower end connected to the slot plane antenna 460,a circular waveguide 463B connected to the upper surface side of thecircular waveguide 463A, and a coaxial waveguide converter 463Cconnected to the upper surface side of the circular waveguide 463B.Furthermore, a rectangular waveguide 463D is connected to the sidesurface of the coaxial waveguide converter 463C and the microwave powersupply 461.

Inside the circular waveguide 463B, an axial portion 462 of anelectroconductive material is coaxially provided, so that one end of theaxial portion 462 is connected to the central (or nearly central)portion of the upper surface of slot plane antenna 460, and the otherend of the axial portion 462 is connected to the upper surface of thecircular waveguide 463B, thereby forming a coaxial structure. As aresult, the circular waveguide 463B is constituted so as to function asa coaxial waveguide. The microwave power can, for example, be betweenabout 0.5 W/cm² and about 4 W/cm². Alternatively, the microwave powercan be between about 0.5 W/cm² and about 3 W/cm². The microwaveirradiation may contain a microwave frequency of about 300 MHz to about10 GHz and the plasma may contain an electron temperature of less thanabout 3 eV, which includes 0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.5, 2, 2.5, or 3eV, or any combination thereof. The plasma may have a density of about1×10¹¹/cm³ to about 1×10¹³/cm³, or higher.

In addition, in the process chamber 450, a substrate holder 452 isprovided opposite the top plate 454 for supporting and heating asubstrate 425 (e.g., a wafer). The substrate holder 452 contains aheater 457 to heat the substrate 425, where the heater 457 can be aresistive heater. Alternatively, the heater 457 may be a lamp heater orany other type of heater. Furthermore the process chamber 450 containsan exhaust line 453 connected to the bottom portion of the processchamber 450 and to a vacuum pump 455.

Still referring to FIG. 8, a controller 499 includes a microprocessor, amemory, and a digital I/O port capable of generating control voltagessufficient to communicate and activate inputs of the plasma processingsystem 410 as well as monitor outputs from the plasma processing system410. Moreover, the controller 499 is coupled to and exchangesinformation with process chamber 450, the vacuum pump 455, the heater457, and the microwave power supply 461. A program stored in the memoryis utilized to control the aforementioned components of plasmaprocessing system 410 according to a stored process recipe. One exampleof controller 499 is a UNIX-based workstation. Alternatively, thecontroller 499 can be implemented as a general-purpose computer, digitalsignal processing system, etc.

Oxidation of a silicon nitride film in the plasma processing system 410can include a substrate temperature between about 25° C. and about 800°C., for example about 400° C. Alternatively, the substrate temperaturecan be between about 400° C. and about 700° C. The pressure in theprocess chamber 450 can, for example, be maintained between about 10mTorr and about 10 Torr, for example about 100 mTorr. Alternatively, thepressure can be maintained between about 20 mTorr and about 1 Torr.According to one embodiment of the invention, the process gas consistsof O₂ that may be introduced into the process chamber 581 at a flow ratebetween about 5 sccm and about 1 slm. According to another embodiment ofthe invention, the process gas can consist of O₂ and an inert gas suchas a noble gas. A flow rate of the inert gas can, for example, bebetween 0 sccm and about 5 slm. In one example, the process gas consistsof O₂ and Ar. Exemplary gas exposure times are between about 5 sec andabout 5 min, for example about 20 sec.

A plurality of embodiments for depositing silicon nitride films andsubsequently forming stressed silicon oxynitride films have beendescribed. The foregoing description of the embodiments of the inventionhas been presented for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise forms disclosed. This description and the claims followinginclude terms that are used for descriptive purposes only and are not tobe construed as limiting. For example, the term “on” as used herein(including in the claims) does not require that a film “on” a substrateis directly on and in immediate contact with the substrate; there may bea second film or other structure between the film and the substrate.

Persons skilled in the relevant art can appreciate that manymodifications and variations are possible in light of the aboveteaching. Persons skilled in the art will recognize various equivalentcombinations and substitutions for various components shown in theFigures. It is therefore intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto.

1. A method of forming a stressed passivation film, comprising:depositing a silicon nitride film over an integrated circuit structureon a substrate; embedding oxygen into a surface of the silicon nitridefilm by exposing the silicon nitride film to a process gas containing anoxygen-containing gas or an oxygen- and nitrogen-containing gas excitedby plasma induced dissociation based on microwave irradiation via aplane antenna member having a plurality of slots, wherein the planeantenna member faces the substrate surface containing the siliconnitride film; and heat-treating the oxygen-embedded silicon nitride filmto form a stressed silicon oxynitride film.
 2. The method of claim 1,wherein the integrated circuit structure comprises: a high-k film formedon the substrate; and a gate electrode film formed on the high-k film.3. The method of claim 1, wherein the embedding further comprises asubstrate temperature between about 25° C. and about 800° C. and aprocess gas pressure between about 10 mTorr and about 10 Torr.
 4. Themethod of claim 1, wherein the process gas further comprises Ar, He, Ne,Xe, or Kr, or two or more thereof.
 5. The method of claim 1, wherein theplasma has a density between about 1×10¹¹/cm³ and about 1×10¹³/cm³ andan electron temperature of less than about 3 eV.
 6. The method of claim1, wherein the plasma originates from a microwave source operating at apower between about 0.5 W/cm² and about 4 W/cm².
 7. The method of claim1, wherein the heat-treating comprises heating the substrate to atemperature between about 500° C. and about 1100° C.
 8. The method ofclaim 7, wherein the heat-treating further comprises exposing thesubstrate to a gas containing O₂, N₂, H₂, Ar, He, Ne, Xe, or Kr, or acombination of two or more thereof.
 9. The method of claim 1, whereinthe oxygen-containing gas comprises O₂, H₂O, or H₂O₂, or a combinationthereof, and the oxygen- and nitrogen-containing gas comprises NO, N₂O,or NO₂, or a combination thereof.
 10. The method of claim 1, wherein thedepositing comprises exposing the substrate to a deposition gascontaining silane, disilane, monochlorosilane, dichlorosilane,trichlorosilane, hexachlorodisilane, tetrakis(dimethylamino)silane,tris(dimethylamino)silane, diethylsilane,tetrakis(ethylmethylamino)silane, bis(diethylamino)silane,bis(di-isopropylamino)silane, tris(isopropylamino)silane,(di-isopropylamino)silane, or bis(tertiarybutylamino)silane, and anitrogen-containing gas comprising N₂, NH₃, N₂H₄, or a C₁-C₁₀alkylhydrazine compound.
 11. The method of claim 1, wherein thedepositing further comprises a substrate temperature between about 400°C. and about 800° C., and a gas pressure between about 0.05 Torr andabout 200 Torr.
 12. The method of claim 1, further comprising: repeatingthe depositing and embedding prior to performing the heat-treating. 13.The method of claim 1, wherein the embedding and heat-treating have atleast partial temporal overlap.
 14. The method of claim 1, wherein theembedding and heat-treating are performed in the same processing system.15. The method of claim 1, wherein the embedding and heat-treating areperformed in different processing systems.
 16. The method of claim 1,wherein a thickness of the silicon nitride film is between about 5 nmand about 50 nm and a thickness of a surface layer containing theembedded oxygen is between about 3 nm and about 10 nm.
 17. A method offorming a semiconductor device, comprising: depositing a silicon nitridefilm over an integrated circuit structure on a substrate, the integratedcircuit structure containing a high-k film formed on the substrate and agate electrode film formed on the high-k film; embedding oxygen into asurface of the silicon nitride film by exposing the silicon nitride filmto a process gas containing an oxygen-containing or an oxygen- andnitrogen-containing gas excited by plasma induced dissociation based onmicrowave irradiation via a plane antenna member having a plurality ofslots, wherein the plane antenna member faces the substrate surfacecontaining the silicon nitride film; and heat-treating theoxygen-embedded silicon nitride film to form the stressed siliconoxynitride film.
 18. The method of claim 17, wherein the plasma has adensity between about 1×10¹¹/cm³ and about 1×10¹³/cm³ and an electrontemperature of less than about 3 eV.
 19. The method of claim 17, furthercomprising: repeating the depositing and embedding prior to performingthe heat-treating.
 20. The method of claim 17, wherein the embedding andheat-treating have at least partial temporal overlap.
 21. The method ofclaim 17, wherein the oxygen-containing gas comprises O₂, H₂O, or H₂O₂,or a combination thereof, and the oxygen- and nitrogen-containing gascomprises NO, N₂O, or NO₂, or a combination thereof.